A turbine includes a turbine rotary shaft which is rotated about an axis, a turbine wheel which is fixed to an outer peripheral side of the turbine rotary shaft, and a housing which covers the turbine wheel. The turbine wheel includes a disk which is fixed to the turbine rotary shaft and a plurality of blades which are provided on an outer peripheral surface of the disk at intervals in a circumferential direction. In portions between the plurality of blades, a working fluid flows in from a portion between leading edges of the blades. The working fluid flows out from a portion between trailing edges of the blades.
In a radial turbine, a leading edge of a blade faces a radially outer side with respect to an axis. In addition, a trailing edge of the blade faces a rear side in an axial direction in which an axis extends. Accordingly, in the radial turbine, the working fluids flows in from a radially outer side and is extracted to the rear side in the axial direction.
For example, as the radial turbine, there is a radial turbine disclosed in the following PTL 1. A pressure surface of the radial turbine forms a concave curved surface which is recessed to a rotation side from the pressure surface toward a suction surface. In addition, the suction surface forms a convex curved surface which protrudes to the rotation side.